Animal Acclimation

Frequently, I am asked about corals that change in appearance or look poorly after being purchased and introduced into a home aquarium. In particular, a coral that looked healthy in the store is introduced into an aquarium, often with what appear to be better conditions that those in which it had previously resided, only to look in a remarkably less healthy condition soon thereafter.

One of the questions I often ask in response to such questions is, "Did you test the bag water or the store water?" The answer is usually, "No." Testing the bagged water is a lesson I learned quite a while ago after enduring far too many inexplicable losses of otherwise apparently healthy livestock. Most aquarists are familiar with drip-type acclimations. The "old-timers rule," based on acclimating freshwater fish, is to make sure the temperature and pH are slowly matched between the bag and the tank, usually through the introduction of small amounts of tank water to the shipping bag. This practice seems fairly common with aquarists whose shipments arrive at the door in a box, and somewhat less common with livestock brought directly home from a local store.

Unfortunately, temperature and pH are not always the whole story, and this is especially true of marine invertebrates. To use corals as an example, I think most people have experienced the relatively long period of time it takes for the average coral to "open up" or acclimate. For some, it may be a period of minutes while for others it may ultimately take months. This "period of adjustment" is a normal biological response of an organism to a new environment and the changes that take place may be truly staggering in terms of number and complexity. Most of the changes are unseen, but are occurring nonetheless.

Acute changes may be obvious. For example, if an animal is plunged from saltwater into freshwater, the changes are usually fast and visually obvious in those animals that manifest behavioral responses. To use a coral example again, the rapid withdrawal of polyps is usually the first response to adverse stimuli. Most aquarists would probably agree that moving a coral from water that is 76oF, with 30ppm of nitrate, a specific gravity of 1.021, 40 watts of fluorescent light, and virtually no water flow to a tank at 82oF, a specific gravity of 1.025, unmeasurable nitrates, 400 watts of metal halide lamps, and strong water flow would be a stressful event that would (and often does) lead to mortality of the organism, despite the fact that the latter conditions may be more natural and better for the long-term health of the organism. However, behavioral responses under such conditions may include self-shading by polyp contraction, sloughing of mucus tunics, catatonia, and death.

What may (or may not) be surprising is that many facilities that sell or trade in livestock have water quality that is less than ideal. The animal or plant purchased at any given time may or may not have spent some considerable acclimatory period in another tank prior to it being purchased by the aquarist. Upon arrival at that same facility, the organism may have looked very similar to the state the aquarist finds it in upon introduction to their tank. Just because something looks healthy, does not in any way suggest that it is healthy. A fish that eats at the store may be eating because it is starving. A coral that is highly expanded at the store may be expanded because it is starving or receiving suboptimal light.

The point here, if it is not already obvious, is that it only makes sense to know what the water quality is from the tank or habitat from whence the organism came. When I collect corals from the wild, I make it a practice to either make subjective notes or directly measure water parameters in order to most accurately reproduce those conditions in an aquarium. When I get a shipment from anywhere, or when I purchase livestock from stores, I ask the facility what their water parameters are, or I directly measure water samples from the packing container or bag.

There are two schools of thought regarding acclimation; to remove an organism as quickly as possible from the poor water conditions and into a tank with presumably good water conditions, treating the shipping event as a temporary acute stress; or to proceed in diligent, careful and slow acclimations in order to pamper an organism through a shipping or transient holding location, treating the event as a chronic stress or an acute stress to which another rapid change is intolerable. The choice of which method to utilize unfortunately depends on the circumstances and the tolerance of the organism. In general, I feel that if something has been in a store for more than a few days and the water quality is significantly different from the aquarists' tank, it has undergone some degree of acclimation and can tolerate, and should likely undergo, a longer more careful acclimation. If the store's water is very similar to that in the destination tank and the organism has been in holding or transit for less than a day, a more rapid transfer to the tank might be preferable.

Comments guys?? I was at an LFS this weekend that claims since he has stopped dripping his stock his losses has decreased dramatically.

Great post copperband !
From what u say it would make sense gettin frags or colonies from a fellow reefers tank, or local propagater,instead of the lfs. seem as though most of us strive for similar climates, thus reducing stress.

That would be great but what are the chances?!?
Our only lfs here, still believes in undergravel filters and oyster shells... is it any wonder all their corals that stay in store more than a month don't make it.

there's always a morality aspect to LFS' but if they not up to scratch i don't support them. Its our job however to inform the non forum members that they have the right to demand proper quality livestock. I've had 5 goldies die on me on the way back from a LFS. Ohh boy did i have a sense of humour failure and got the fish replaced. I don't buy from shops that are not up to standard.

I made a post on marine LFS's on a FW forum during december last year. I'll find out if I can post it here. Wasn't pretty!!